JPH11340278A - Resin sheet for mounting semiconductor device, flip chip mounting method and circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flip chip mounting method and a resin sheet for mounting a semiconductor device and a circuit board used for it, capable of simultaneously performing the electric connection and mechanical connection by resin of the semiconductor device and the circuit board, and improving reliability by completely sealing the semiconductor device to four corners. SOLUTION: At the time of mounting the semiconductor device 10 and the circuit board 20, this resin sheet 30 is stuck to the loading part of the semiconductor device 10 on the circuit board 20 first. For the resin sheet 30, the four corners (thick film parts) 31 are formed thicker than a center part. Mounting is performed by positioning, heating and loading an electrode group 12 and the electrode group 21. The resin sheet 31 is softened and fluidized by the heating and loading, surrounds the semiconductor device 10, is hardened by later temperature drop, and seals the semiconductor device 10 to the four corners.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin sheet for encapsulating a semiconductor used when mounting a semiconductor device on a circuit board, a method for mounting the semiconductor device, and a circuit board.

[0002]

2. Description of the Related Art Conventionally, in flip-chip connection, in which a semiconductor device is directly mounted on a circuit board in a bare chip state, a bump electrode formed on an electrode of the semiconductor device and a corresponding electrode of the circuit board are aligned and added. Electrical connection is made by pressure and heat, and then a thermosetting or photocurable liquid resin is injected into the gap between the semiconductor device and the circuit board, and the resin is cured to seal the semiconductor device and the circuit. The mechanical connection with the substrate was strengthened.

FIGS. 23 (a) to 23 (c) show an example of a conventional flip chip connection method, in which 10 is a semiconductor device, 11 is an electrode formed on the semiconductor device, and 12 is a gold protrusion. Electrodes, 20 is a circuit board, 21 is an electrode formed on the circuit board, and 60 is a sealing resin.

Here, a conventional flip chip connection process will be described. First, as shown in FIG. 23A, Au bump electrodes are formed on the electrodes 11 of the semiconductor device 10 by a ball bumping method or a plating method, and if necessary, the height of the Au bump electrodes is adjusted. Leveling is performed.

Next, as shown in FIG. 23B, alignment between the protruding electrode 12 on the semiconductor device 10 and the electrode 21 on the circuit board 20 is performed, and the protruding electrode 1 on the semiconductor device 10 is aligned.
2 and the electrode 21 on the circuit board 20 are brought into contact with each other, and are electrically connected by applying pressure and heating.

Finally, as shown in FIG. 10C, a dispenser 8 is provided in a gap between the semiconductor device 10 and the circuit board 20.
After the liquid resin 60 is injected using 0 or the like, the resin is heated and cured to complete the resin sealing.

However, such a conventional flip chip connection has the following disadvantages. An electrical connection step between the semiconductor device and an electrode of the circuit board;
Two steps of sealing the gap between the semiconductor device and the circuit board are required.

If the sealing resin is to be injected into the gap between the semiconductor device and the circuit board after the semiconductor device is electrically connected to the circuit board, an area for dropping the liquid resin is required,
Requires extra space on the circuit board.

The gap between the semiconductor device and the circuit board is 20 to 5
If the width is as small as 0 μm, the sealing resin does not sufficiently flow into the inside, air remains in the sealing resin, and bubbles 7
0 occurs. In this case, the air trapped in the gap between the semiconductor device and the circuit board causes the moisture contained therein to diffuse into the sealing resin, and as a result, the moisture penetrates to the electrode portion for electrical connection, and the gap between the electrodes is reduced. In some cases, there may be a problem with the insulation reliability of the device.

Although the sealing resin has the effect of enhancing the mechanical connectivity between the semiconductor device and the circuit board, the bonding area of the sealing resin is reduced by bubbles, and the mechanical connection strength between the semiconductor device and the circuit board is reduced. This causes a problem in reliability against thermal stress and mechanical stress.

In order to solve these problems, methods described in Japanese Patent No. 2647047, Japanese Patent Application Laid-Open No. 6-104311 and Japanese Patent Application Laid-Open No. 9-97815 are known. In these inventions, an insulating resin sheet for sealing is interposed in advance at the time of flip-chip connection, an electrical connection step between the semiconductor device and the circuit board, and a sealing step between the semiconductor device and the circuit board. At the same time to prevent the entrapment of air bubbles in the sealing resin and to simplify the process.

[0012]

However, the prior art has the following problems. JP-A-6-1043
The insulating resin sheet used in the method described in Japanese Patent Application Laid-Open No. 11-1995 and Japanese Patent Application Laid-Open No. 9-97815 is a process for forming fine holes of approximately electrode size at positions corresponding to the electrode formation positions of the semiconductor device. In the process of attaching the insulating resin sheet, it is necessary to precisely align the holes formed with the electrodes of the circuit board or the electrodes of the semiconductor device. In addition, it is difficult to form a fine hole, and when the electrode pitch of the semiconductor device is reduced, holes formed in the insulating resin sheet may be connected to each other.

As another means, as shown in FIG. 24, a sheet-like sealing resin 22 for a semiconductor device is pasted or printed in a region inside the electrode group of the semiconductor device 10 so that the semiconductor device 10 and the circuit are connected to each other. Pressurization when connecting to the substrate 20,
The connecting portion was sealed by spreading the resin 22 by the heating process and flowing the resin 22 to the electrode connecting portion of the semiconductor device.
In order to minimize the surface area, a large amount of resin is protruded near the center of the side of the semiconductor device as shown in FIG. It is incomplete. For this reason, there is a disadvantage that the reliability of the connection portion that is not sufficiently sealed is inferior. In the case where the semiconductor device is packaged by transfer molding after flip-chip connection, the semiconductor device 1
There is a problem that the connection portion is broken because the mold resin enters the gap between the circuit board 20 and the circuit board 20.

Further, in the method described in Japanese Patent No. 2647047, by using a sheet-like adhesive which is raised so that the central portion has the maximum thickness, air bubbles are not trapped between the semiconductor device and the circuit board. I have. However, in this method, a sheet having a size larger than that of the semiconductor device is used, and a resin is interposed between the protruding electrodes of the semiconductor device and the electrodes of the substrate, so that connection reliability is reduced. In order to avoid such a situation, it is sufficient to dispose the sheet-shaped resin only in a region inside the electrode, but in this case, as described above, a problem arises in that the vicinity of the corner of the semiconductor device is not sufficiently sealed. I will.

The present invention has been made to solve the above-mentioned problems, and it is possible to simultaneously perform electrical connection between a semiconductor device and a circuit board and mechanical connection using a resin, and completely seal the semiconductor device to four corners. It is an object of the present invention to provide a flip-chip mounting method capable of improving reliability, a resin sheet for mounting a semiconductor device used in the method, and a circuit board.

[0016]

A semiconductor device mounting resin sheet according to claim 1 is interposed between a semiconductor device and a circuit board, and flows and deforms due to heating during mounting, so that the semiconductor device and the semiconductor device are bonded to each other. A resin sheet for mounting a semiconductor device, which is mechanically connected to a circuit board, has a portion thicker than a central portion at four diagonal corners.

The resin sheet for mounting a semiconductor device according to claim 2 is interposed between the semiconductor device and the circuit board, and flows and deforms by heating during mounting to mechanically connect the semiconductor device and the circuit board. In the resin sheet for mounting a semiconductor device to be connected to the semiconductor device, notches for increasing the thickness of the four diagonal corners by bending are formed.

It is to be noted that the diagonal 4 in claims 1 and 2
The corners mean the four corners if the resin sheet has a rectangular shape, but are not limited thereto. If the resin sheet is not rectangular, the four corners are the diagonals furthest from the center of the resin sheet.
The corner.

A flip-chip mounting method according to claim 3, wherein the semiconductor device is mounted on the circuit board by connecting a semiconductor electrode group of the semiconductor device to a substrate electrode group formed on a circuit board. In the chip mounting method, in a region inside the semiconductor electrode group on the circuit board or in a region inside the substrate electrode group in the semiconductor device, portions corresponding to the four corners of the semiconductor device are located at a center portion. A step of attaching a thick resin sheet, a step of positioning the semiconductor device and the circuit board so as to face each other, and bringing the semiconductor electrode group and the board electrode group into contact with each other, and applying pressure and heat. Simultaneously performing the electrical connection between the electrodes and the mechanical connection and sealing of the semiconductor device and the circuit board by the resin sheet. It is intended.

According to a fourth aspect of the present invention, in the circuit board on which the semiconductor device is mounted, a portion corresponding to the four corners of the semiconductor device in a region where the semiconductor device is mounted is different from other portions. It is formed so as to protrude toward the mounting surface side. This protruding portion is made of, for example, a resin layer formed on a circuit board.

According to a fifth aspect of the present invention, in the flip chip mounting method, the semiconductor device is mounted by connecting a substrate electrode group formed on the circuit board according to the fourth aspect to a semiconductor electrode group of the semiconductor device. In a flip chip mounting method for mounting on a circuit board, a step of attaching a resin sheet to a region inside the semiconductor electrode group on the circuit board or a region inside the substrate electrode group in the semiconductor device, A step of positioning the semiconductor device and the circuit board so as to face each other, bringing the semiconductor electrode group and the board electrode group into contact with each other, applying pressure and heating, and electrically connecting the semiconductor electrodes and the resin sheet. Simultaneously performing mechanical connection and sealing between the semiconductor device and the circuit board.

According to a sixth aspect of the present invention, in the circuit board on which the semiconductor device is mounted, a dam for suppressing the flow of the sealing resin is formed outside a region where the semiconductor device is mounted. Things.

According to a seventh aspect of the present invention, in the flip chip mounting method, the semiconductor device is connected to a substrate electrode group formed on the circuit board according to the sixth aspect by connecting the semiconductor electrode group of the semiconductor device. In a flip chip mounting method for mounting on a circuit board, a step of supplying a sealing resin to a region inside the semiconductor electrode group on the circuit board or a region inside the substrate electrode group in the semiconductor device. Positioning the semiconductor device and the circuit board so as to face each other, bringing the semiconductor electrode group and the substrate electrode group into contact with each other, applying pressure and heating, and electrically connecting the semiconductor electrodes and the sealing. Simultaneously performing the mechanical connection and sealing of the semiconductor device and the circuit board with the resin for use.

In the flip chip mounting method according to the present invention, the semiconductor device is mounted on the circuit board by connecting a substrate electrode group formed on the circuit board to a semiconductor electrode group of the semiconductor device. In the flip-chip mounting method, a step of supplying a sealing resin to a region inside the semiconductor electrode group on the circuit board or a region inside the substrate electrode group in the semiconductor device; and A step of positioning the circuit board so as to face the same, a step of arranging a sealing resin shaping member around a mounting area of the semiconductor device in the circuit board, and in a state where the sealing resin shaping member is arranged, The semiconductor electrode group and the substrate electrode group are brought into contact with each other, pressurized and heated to electrically connect the semiconductor electrode group and the substrate electrode to the semiconductor device and the circuit. And performing the mechanical connection and the sealing of the substrate at the same time, it is intended to include.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> An embodiment of the present invention will be described below with reference to the drawings. FIG.
FIG. 1 is a cross-sectional view illustrating a flip-chip mounting structure according to an embodiment of the present invention. In this flip chip mounting structure,
Electrodes are formed on two opposing sides of the semiconductor device electrode formation surface, and a bump electrode 12 is formed on the semiconductor device 10 in advance. Here, an Au bump formed by a ball bumping method using an Au wire is used as the bump electrode 12. Of course, it is also possible to form a protruding electrode by electrolytic or electroless plating.

The semiconductor device 10 has an electrode 21 formed on the circuit board 20 in a state in which the surface on which the electrode 11 is formed faces the circuit board 20, that is, in a face-down manner.
(The outermost layer is made of Au) and are electrically connected by Au-Au solid phase diffusion bonding. The connection reliability is improved by the sealing resin 32 interposed between the semiconductor device 10 and the circuit board 20.

In the semiconductor mounting structure having such a structure, the encapsulating resin 32 is connected to the semiconductor device 10 and the circuit board 2 simultaneously with the Au-Au solid phase diffusion bonding between the semiconductor device 10 and the circuit board 20.
By flowing between 0 and 0, the semiconductor device 10 and the circuit board 20 are mechanically connected and sealed. Hereinafter, a process of forming the present semiconductor mounting structure will be described.

(Step 11) First, as shown in FIG. 3, a region 22 (hatched portion) sandwiched between electrode groups 21 present on two opposite sides of a semiconductor device mounting region on a circuit board 20 made of a polyimide substrate, A cured resin sheet 30 having a low coefficient of thermal expansion is attached. At this time, the resin sheet 3
0 denotes the protruding electrode 12 on the semiconductor device 10 and the circuit board 20
Considering the electrical connection with the upper electrode 21, the circuit board 2
It is desirable to arrange so as not to cover the electrode 21 formed on the zero. In addition, the resin sheet 30 flows and deforms when the semiconductor device is mounted, and becomes the sealing resin 32 in FIG.

FIG. 1 is an enlarged view of the resin sheet 30 ((a)).
Is a cross-sectional view, and (b) is a plan view). As shown in this figure, the resin sheet 30 is located near the four corners of the semiconductor device 10.
1 (hereinafter referred to as a thick film portion) is formed to be thicker than other portions.

As shown in FIG. 2, the connection reliability between the protruding electrode 12 formed on the semiconductor device 10 and the electrode 21 of the circuit board 20 is protected by the mechanical strength due to the adhesive force of the sealing resin 32. . In order to sufficiently cover the electrode connection portion with the sealing resin 32, the thickness of the central portion of the resin sheet 30 is 5 μm larger than the gap h1 between the electrode forming surface of the semiconductor device 10 after flip-chip mounting and the surface of the circuit board 20. It is desirable to use a thicker one or more, and the thick film part 31
It is desirable that the sealing resin 32 be formed to have a sufficient thickness so as to protrude from the semiconductor device 10 when mounted and to cover the corner. For example, if the bump height after connection is about 30 μm, it is appropriate that the thickness of the resin at the center is about 35 to 40 μm and the thickness of the thick film part 31 is about 60 to 70 μm. The formation range of the thick film portion 31 is appropriately selected depending on the size of the semiconductor device 10 and the arrangement of the electrodes 11.
For example, a radius of 50 to 5 around the corner of the semiconductor device 10
It is formed in a range of about 00 μm.

The resin material of the resin sheet 30 may be a thermoplastic resin having the property of being softened by heating or flowing when melted, such as epoxy or polyimide. In addition, resin sheet 3
It is desirable to control 0 to an appropriate coefficient of thermal expansion or elasticity in order to enhance connection reliability. The coefficient of thermal expansion is
It varies depending on the type of resin, but is generally 10-100p
pm / ° C.

In this embodiment, the thickness of the central portion is 40 mm.
A μm resin sheet was used. The thickness of the thick film portion 31 corresponding to the vicinity of the corner of the semiconductor device (if the size of the semiconductor device is about 7 × 5 mm, the radius may be about 500 μm from the corner) may be sufficient if the sealing resin 32 is sufficient for the semiconductor device. In order to protrude from 10 and cover the corner, the thickness was 60 μm. In addition, although polyimide is used as the resin material of the resin sheet 30, polyimide is suitable for Au-Au connection that requires high-temperature bonding because of its excellent heat resistance.
The coefficient of thermal expansion of the polyimide sheet was 38 ppm.

(Step 12) Next, as shown in the sectional view of the bonding step of FIG.
The back surface of the semiconductor device 10 with the protruding electrodes 12 leveled to 0 μm is placed on the semiconductor device pressing tool 40
And the electrode 2 of the circuit board 20 arranged on the bonding stage 65 with the protruding electrode 12 of the semiconductor device 10.
Positioning with 1 is performed.

(Step 13) The semiconductor device 10
The semiconductor device pressing tool 40 is set to 50 μm / s
The semiconductor device pressing tool 40 is lowered at the following low speed. At this time, since the protruding electrode 12 of the semiconductor device 10 protrudes most, the protruding electrode 12 first contacts the electrode 21 on the circuit board 20. At about the same time as the contact, the semiconductor device pressing tool 40 and the bonding stage 65 start to be heated by the pulse heating method.

(Step 14) After the contact, a load is gradually applied to the protruding electrode 12 so that the height of the protruding electrode 12 is about 50 μm.
Is compressed to about 30 μm. At this time, the resin sheet 3
With respect to 0, the thick film portion 31 is first loaded, and then the central portion is loaded, and the resin sheet 30 is softened by heating from the semiconductor device pressing tool 40. And spread over the entire surface on which the electrodes are formed.

Since the resin sheet 31 tends to spread in a circular shape, if the thick film portion 31 is not formed (that is, if the thickness of the resin sheet 31 is formed uniformly), the side of the side of the semiconductor device 10 is formed. The sealing resin protrudes largely near the center, but runs short near the corner (see the top view in FIG. 5). However, in the present embodiment, the resin sheet 31
Since the corners of the semiconductor device have a thick film, which is sufficiently thicker than the connection height, the corners of the semiconductor device can be covered.

(Step 15) Subsequently, while maintaining the temperature of the junction at 350 ° C., the Au bump electrode 1 of the semiconductor device 10 is
2 and Au formed on the surface of the electrode 21 of the circuit board 20 to perform Au-Au solid phase diffusion bonding.

(Step 16) Thereafter, the resin sheet 31 which has flowed and been deformed by lowering the temperature is cured to form the sealing resin 32, and the mounting process is completed.

At this time, the gap between the electrode forming surface of the semiconductor device 10 and the circuit board 20 is about 30 μm. The shape of the sealing resin 32 is as shown in the top view of FIG.
The corners of the semiconductor device are completely sealed.

At this time, the semiconductor device 10 and the circuit board 20
Is filled with a sealing resin 32 having a coefficient of thermal expansion of about 10 to 100 ppm. Even when Au-Au bonding is performed in the thermally expanded state of the connecting step and the temperature is returned to room temperature, the residual stress is not reduced. It can be reduced to the extent that reliability is not affected.

Through the above steps, the flip chip mounting structure shown in FIG. 2 can be finally obtained. In this mounting structure, the semiconductor package shown in FIG. 7 can be obtained by performing sealing resin potting 40 on the semiconductor device 10. Further, the mounting structure is resin-molded 41 by a transfer molding method, and the circuit board 2 is formed.
The semiconductor package shown in the cross-sectional view of FIG. 8 can be obtained by providing a through hole at 0 and forming a solder ball 42 in the through hole. As shown in FIG. 9, the external electrodes 4 are formed by electrodes formed on the peripheral portion of the circuit board 20.
It is also possible to take out 3 and obtain what is called LCC (leadless chip char).

It should be noted that these semiconductor packages obtained by the present technology have a feature that the size of the package is not so large as compared with the size of the semiconductor device. These package structures are examples, and the present invention is not limited to these.

In this embodiment, the case where the electrodes of the semiconductor device are formed on two sides has been described. However, the same effect can be obtained even if the electrodes are formed on three or four sides. Not something.

<Second Embodiment> FIG. 10 shows a second embodiment.
FIG. 3 is a cross-sectional view showing the mounting structure of FIG. In this flip-chip mounting structure, the electrodes 11 formed on two sides of the electrode forming surface of the semiconductor device 10 are formed on the electrodes 21 in the semiconductor device mounting region on the substrate 20 in advance.
3 is electrically connected. In the present embodiment, A formed by a ball bumping method using an Au wire
The u bump was used as the bump electrode 13. The semiconductor device 10 has an electrode formation surface facing the substrate 20, that is, an Au of a surface Al electrode of the semiconductor device 10 and an Au projection electrode 13 formed on the substrate 20 in a face-down manner.
-Electrical connection is made by Al solid phase diffusion bonding. In addition, by interposing the sealing resin 32 between the semiconductor device 10 and the substrate 20, the connection reliability is improved by the adhesive force, and the semiconductor device 10 is sealed.

In this embodiment, the sealing resin 32 is formed by flowing, deforming, and hardening a resin layer 23 and a resin sheet 33 described later. Hereinafter, the manufacturing process of the mounting structure illustrated in FIG. 10 will be described.

(Step 21) First, as shown in FIG. 11 (a) sectional view and FIG. 11 (b) plan view, the area of the circuit board 20 where the semiconductor device 10 is mounted In the inner region, around the four corners of the semiconductor device 10,
A resin layer 23 made of polyimide is formed. Resin layer 23
If the size of the semiconductor device 10 is about 10 × 10 mm, the range of about 500 μm from the corner of the semiconductor device 10 is appropriate. Further, since the distance between the semiconductor device 10 and the circuit board 20 after flip-chip connection is about 40 μm,
The thickness of the resin layer 23 was 30 μm.

(Step 22) Subsequently, as shown in FIG. 11A, the resin sheet 33 is placed in a region surrounded by the wiring electrode groups 24 formed on two sides on the electrode forming surface of the semiconductor device 10. paste. At this time, in consideration of the electrical connection between the electrodes 11 on the semiconductor device 10 and the protruding electrodes 13 on the substrate 20, it is desirable that the resin sheet 33 does not cover the electrodes 11 formed on the semiconductor device 10. .

The connection reliability between the electrode 11 formed on the semiconductor device 10 and the protruding electrode 13 on the substrate 20 depends on the sealing resin material 3
2 is protected by the mechanical strength of the adhesive force. The thickness of the resin sheet 33 is determined in consideration of this point. For example, a resin sheet 33 having a thickness about 5 μm thicker than the gap h2 between the electrode forming surface of the semiconductor device 10 after flip-chip mounting and the surface of the substrate 20 is used. In the present embodiment, a resin sheet 33 having a thickness of 50 μm is used.

(Step 23) Next, as shown in the sectional view of the bonding step in FIG. 11A, the back surface of the semiconductor device 10 is vacuum-sucked by the semiconductor device pressing tool 40 of the bonding device, and the electrode 11 of the semiconductor device 10 is removed. And the electrode height of the circuit board 20 placed on the bonding stage 65 is about 60
Positioning with the protruding electrode 23 leveled to μm is performed.

(Step 24) Next, when approaching the semiconductor device 10, the semiconductor device pressing tool 40 is lowered at a low speed of 50 μm / s or less. At this time, the protruding electrode 13 that protrudes most is the electrode 11 on the semiconductor device 10.
Abut. Almost simultaneously with the contact, the semiconductor device pressing tool 40 and the bonding stage 65 start to be heated by the pulse heating method.

(Step 25) A load is gradually applied to the projecting electrode 13 to compress the projecting electrode 13 having a height of about 60 μm to about 40 μm. At this time, a load is applied to the polyimide resin layer 23 formed on the circuit board 20 and the resin sheet 33 thereabove.
And the resin sheet 33 is softened by heating,
It spreads over the entire electrode forming surface of the semiconductor device 10.

At this time, since the resin sheet 33 tends to spread in a circular shape, the resin protrudes largely in the vicinity of the center of the side of the semiconductor device 10 without the resin layer 23, but short in the vicinity of the corner. However, the resin sheet 33 on the resin layer 23
Is supplied, the resin in the vicinity of the corner of the semiconductor device 10 largely protrudes, and it is possible to sufficiently cover the corner.

(Step 26) Subsequently, the temperature of the junction is maintained at 300 ° C., and the Au—Al is formed by joining the Al electrode 11 of the semiconductor device 10 and the Au projection electrode 13 of the substrate 20.
Perform solid phase diffusion bonding.

(Step 27) Thereafter, the temperature is lowered and the resin sheet 33 and the resin layer 23 are cured to form the sealing resin 32, and the mounting process is completed.

At this time, the gap between the electrode forming surface of the semiconductor device 10 and the substrate 20 is about 40 μm. Further, the shape of the sealing resin 32 is as shown in the top view of FIG. 6, and the corners of the semiconductor device are completely sealed.

In this embodiment, the circuit board is made of Au.
Although the case where the protruding electrode is formed and joined to the Al electrode of the semiconductor device has been described, as the protruding electrode for performing the electrical connection, a Au or Au alloy protruding electrode may be formed on both the semiconductor device and the substrate. Also, an Au protruding electrode is formed on the semiconductor device side and a solder protruding electrode is formed on the substrate side, and bonding at a lower temperature than in this embodiment is possible.

In this embodiment, the case where the electrodes of the semiconductor device are formed on two sides has been described. However, the same effect can be obtained even if the electrodes are formed on three or four sides. It is not something to be done.

Further, the mounting structure obtained according to the present embodiment can be formed into a semiconductor package by resin molding as in the first embodiment.

<Embodiment 3> FIGS. 12A and 12B are views showing a flip-chip mounting structure according to the present embodiment (FIG.
(B) Plan view). This mounting structure is a semiconductor device 1
A dam 24 for damping the sealing resin 32 around 0 is provided. The sealing resin 32 is formed by flowing, deforming, and hardening a resin 34 described later. This mounting structure is formed as follows.

(Step 31) First, a dam 24 made of polyimide is provided in a region of the circuit board 20 outside the region where the semiconductor device 10 is mounted so as to surround the semiconductor device. The thickness of the polyimide 24 may be appropriately selected,
Since the height of the connection of the semiconductor device 10 needs to be higher and the flow of the sealing resin 32 needs to be changed, the thickness is set to about 100 μm.

(Step 32) As shown in FIG. 12, the resin 3
4 is supplied by printing. At this time, it is desirable that the resin 34 does not cover the electrodes 21 of the circuit board 20 in consideration of the electrical connection between the electrodes 11 on the semiconductor device 10 and the electrodes 21 on the circuit board 20. The bump electrode 12 made of Au formed on the semiconductor device is coated with Ag or Pd by a known method.
Is supplied.

(Step 33) Next, as shown in the cross-sectional view of the bonding process in FIG. 13, the back surface of the semiconductor device 10 is vacuum-sucked by the semiconductor device pressing tool 40 of the bonding device, and the conductivity is controlled to a constant thickness. The conductive paste 14 is supplied onto the bump electrodes 12 by bringing the bump electrodes 12 into contact with the paste.

(Step 34) Subsequently, the semiconductor device 10
The Au projection electrode 12 formed on the electrode 11 is aligned with the electrode 21 of the substrate 20 arranged on the bonding stage 65.

(Step 35) Next, when approaching the semiconductor device 10, the semiconductor device pressing tool 40 is lowered at a low speed of 50 μm / s or less. At this time, the protruding protruding electrode 12 comes into contact with the electrode 21 on the circuit board 20. Almost simultaneously with the contact, the semiconductor device pressing tool 40 and the bonding stage 65 start to be heated by the pulse heating method.

(Step 36) A load is gradually applied to the protruding electrode 12 to remove the protruding electrode 12 having a height of about 60 μm.
Compress to 0 μm. At this time, a load is applied to the resin 34 printed on the circuit board 20.
Is softened by heating and spreads. At the same time, the conductive paste 14 supplied to the protruding electrodes 12 is cured by heating, and an electrical connection is obtained.

By applying a load when the semiconductor device is connected, the resin 34 spreads over the entire active surface of the semiconductor device 10. At this time, since the resin 34 tends to spread in a circular shape, the resin 34 largely protrudes from the vicinity of the center of the side of the semiconductor device 10 and protrudes and hits the dam 24 made of polyimide. The resin that has sequentially protruded from the vicinity of the center of the side of the semiconductor device 10 is sandwiched by the dam 24 made of polyimide, changes the flowing direction, and flows so as to cover the vicinity of the corner of the semiconductor device 10.

(Step 37) Thereafter, the resin 34 is cured by the temperature drop to form the sealing resin 32, and the mounting process is completed.

By this step, the sealing resin has a shape as shown in FIG. 14 and is completely sealed up to the corners of the semiconductor device.

In this embodiment, the case where the electrodes of the semiconductor device are formed on two sides has been described. However, the same effect can be obtained even if the electrodes are formed on three or four sides. Not something.

Further, the mounting structure obtained according to the present embodiment can be resin-molded into a semiconductor package as in the first embodiment.

<Fourth Embodiment> FIG. 15 is a cross-sectional view for explaining a manufacturing process of a mounting structure according to the present embodiment. In the present embodiment, a process for manufacturing the mounting structure shown in FIG. 18 will be described. Note that the sealing resin 32 in FIG.
The resin sheet 35 in 5 is formed by flowing, deforming, and hardening.

(Step 41) First, as shown in FIG. 15, a region having a low coefficient of thermal expansion is hardened in a region sandwiched between electrode groups 21 existing on two opposite sides of a semiconductor device mounting region on a circuit board 20 made of a polyimide base material. Resin sheet 35
Paste. At this time, in consideration of the electrical connection between the protruding electrodes 12 on the semiconductor device 10 and the electrodes 21 on the circuit board 20, the resin sheet 35 may not cover the electrodes 21 formed on the circuit board 20. desirable.

Projection electrode 12 formed on semiconductor device 10
The connection reliability between the circuit board 20 and the electrodes 21 is protected by mechanical strength due to the adhesive force of the sealing resin 32. In order to increase the bonding area of the resin sheet 35, the thickness of the resin sheet 35 is For example, it is desirable that the gap between the electrode forming surface of the semiconductor device 10 after flip-chip mounting and the surface of the substrate 20 is about 5 μm thicker. In the present embodiment, the resin sheet 35 having a thickness of 45 μm is used.

(Step 42) Next, as shown in the cross-sectional view of the bonding process in FIG. 15, the back surface of the semiconductor device 10 with the protruding electrodes 12 whose electrode height is leveled to about 50 μm is pressed by the semiconductor device pressing tool 40 of the bonding device. Then, the projection electrode 12 of the semiconductor device 10 and the electrode 21 of the circuit board 20 arranged on the bonding stage 65 are aligned.

(Step 43) Next, as shown in FIG. 16, before the semiconductor device 10 is brought into contact with the circuit board 20,
First, a resin shaping tool (a sealing resin shaping member) 90 is brought into contact with the circuit board 20. Then, as shown in FIG.
By lowering the semiconductor device pressing tool 40 at a low speed, the protruding electrode 12 of the semiconductor device 10 projecting most is
The semiconductor device pressing tool 40 and the bonding stage 65 are started to be heated by a pulse heating method almost simultaneously with the upper electrode 21.

(Step 44) Subsequently, a load is gradually applied to the projecting electrode 12 to compress the projecting electrode 12 having a height of about 50 μm to 45 μm. At this time, the resin sheet 3
5 is also applied, and the resin sheet 35 is softened by heating from the semiconductor device pressing tool 40, so that the resin sheet 35 is pushed and spread over the entire surface of the semiconductor device electrode formation surface. Eventually, it protrudes outside the semiconductor device 11 and contacts the resin shaping tool 90. As the amount of protrusion of the resin increases, the resin spreads inside the shaping tool 90 and finally reaches the corner of the semiconductor device 10.

(Step 45) Subsequently, while maintaining the temperature of the junction at 350 ° C., the Au bump electrode 1 of the semiconductor device 10 is
Au—Au diffusion bonding is performed by bonding Au and Au formed on the surface of the electrode 21 of the circuit board 20.

(Step 46) Thereafter, the resin sheet 35 which has flowed and been deformed due to the temperature drop is hardened to form the sealing resin 32.

(Step 47) Next, the resin shaping tool 9
Then, the bonding tool 40 is raised (see FIG. 18). Note that the semiconductor device 10 at this time is
The gap between the electrode forming surface and the substrate 20 is about 30 μm.
By this step, the sealing resin 32 has a shape as shown in FIG. 14 and is completely sealed up to the corners of the semiconductor device.

In this embodiment, the case where the electrodes of the semiconductor device are formed on two sides has been described. However, the same effect can be obtained even if the electrodes are formed on three or four sides. Not something.

Further, the mounting structure obtained according to the present embodiment can be resin-molded into a semiconductor package as in the first embodiment.

<Fifth Embodiment> FIG. 19 is a perspective view showing a manufacturing process of a flip-chip mounting structure according to another embodiment of the present invention. In this embodiment, the electrodes 21 are formed on four sides of the semiconductor device electrode formation surface, and the protruding electrodes 12 are formed in advance on the circuit board at positions corresponding to the electrodes 11 on the semiconductor device 10. Here, Au formed by a ball bumping method using an Au wire is used.
The bump was used as the bump electrode 12. It is also possible to form a protruding electrode by electrolytic or electroless plating.

The semiconductor device 10 has a state in which the surface on which the electrodes 11 are formed faces the circuit board 20, that is, the outermost layer formed on the circuit board 20 in a face-down manner is A
Electrical connection is made with the electrode 21 made of u by Au-Au solid phase diffusion bonding. The connection reliability is improved by a sealing resin interposed between the semiconductor device 10 and the circuit board 20.

As shown in FIG. 20 (a), the resin sheet 50 has T-shaped cuts 4 at two opposing sides of a rectangular sheet.
5, and the thickness of the corner portion can be increased by folding back as shown in FIG. For example, if the bump height after connection is about 30 μm, the resin sheet 50 has a resin thickness of 30 to 35 μm.
By folding the T-shaped portion, the area near the four corners (thick film portion) 31 becomes 60 to 70 μm, which is a thickness suitable for sealing the semiconductor device.

Further, the resin sheet may be a resin sheet 53 manufactured in a process as shown in FIG. A liquid thermoplastic resin 52 is dropped onto a sheet-like sealing material 51 made of a thermoplastic resin. Next, a resin sheet partially raised by curing in an oven is formed. Note that the liquid thermoplastic resin 52 is dropped on a portion corresponding to a corner of the semiconductor device. Then, as shown in FIGS. 22 (a) and (b), by dividing the raised portion into four equal parts,
A resin sheet 53 having a large corner portion can be obtained.

As the encapsulating resin material, epoxy, polyimide, or the like is often used, but any thermoplastic resin having the property of being softened by heating or flowing when melted may be used.

The mounting structure shown in FIG. 19 is manufactured by the following steps. (Step 51) First, as shown in FIG. 19, a region 22 (hatched portion) sandwiched between electrode groups 21 present on four sides in a semiconductor device mounting region on a circuit board 20 of a polyimide base material.
The resin sheet 50 (FIG. 20) or 53 (FIG. 22)
Paste. At this time, the resin sheets 50 and 53 do not cover the electrodes 21 formed on the circuit board 20 in consideration of the electrical connection between the protruding electrodes 12 on the semiconductor device 10 and the electrodes 21 on the circuit board 20. It is desirable. The connection reliability between the protruding electrode 12 formed on the semiconductor device 10 and the electrode 21 of the circuit board 20 is protected by the mechanical strength due to the adhesive force of the resin. The thickness of the resin sheets 50 and 53 depends on the electrode forming surface of the semiconductor device 10 after flip-chip mounting and the circuit board 2.
A material having a thickness of about 5 μm or more than the gap h1 with the surface 0 is used. In the present embodiment, a material having a thickness of 30 to 35 μm is used. In the case of the resin sheet 50, the thickness of the portion corresponding to the vicinity of the corner of the semiconductor device is 60 to 70 μm in order to fold the resin sheet. The resin sheet 53 has a thickness of about 40 to 70 μm.

(Step 52) Next, the electrode height is set to about 40
Semiconductor device 1 with bump electrode 12 leveled to μm
0 is vacuum-sucked by the semiconductor device pressing tool 40 of the bonding apparatus, and the protruding electrodes 12 of the semiconductor device 10 and the electrodes 21 of the circuit board 20 disposed on the bonding stage 65.
Align with.

(Step 53) Subsequently, the semiconductor device 10
When the semiconductor device 10 comes into contact with the semiconductor device 10, the semiconductor device pressing tool 40 is lowered at a low speed of 50 μm / s or less so that the most protruding semiconductor device 10 comes into contact with the electrode 21 on the circuit board 20. The heating of the tool 40 and the bonding stage 65 is started by the pulse heating method.

(Step 54) Subsequently, a load is gradually applied to the protruding electrode to remove the protruding electrode having a height of about 40 μm.
Compress to about 0 μm. At this time, the resin sheet 50,
In 53, a load is first applied to a thick portion, and then a load is applied to a central portion. Since the resin sheets 50 and 53 are softened by heating from the semiconductor device pressing tool 40,
By applying a further load, the resin sheets 50 and 53 spread over the entire surface of the semiconductor device 10 on which the electrodes are formed.

Since the resin sheets 50 and 53 tend to spread in a circular shape, if there is no thick part in the resin sheets 50 and 53, the resin sheets 50 and 53 protrude largely in the vicinity of the center of the side of the semiconductor device, but short in the vicinity of the corner. However, in this embodiment, since the resin sheets 50 and 53 are interposed, the corners of the semiconductor device 10 can be covered.

(Step 55) Next, the temperature of the joint is set to 3
The semiconductor device 10 is maintained at 50 ° C.
Au-Au solid-phase diffusion bonding is performed by bonding Au and Au formed on the surface of the electrode 21 of the substrate 20.

(Step 56) Thereafter, the temperature is lowered and the resin sheets 50 and 53 are cured, and the mounting process is completed. At this time, the gap between the electrode forming surface of the semiconductor device 10 and the circuit board 20 is about 30 μm. The gap between the semiconductor device 10 and the circuit board 20 is 10 to
Thermosetting resin 50 having a coefficient of thermal expansion of about 100 ppm
And Au- in the thermally expanded state of the connection process.
Even when Au bonding is performed and the temperature is returned to room temperature, the residual stress can be reduced to such an extent that reliability is not affected.

In this embodiment, the case where the electrodes of the semiconductor device are formed on four sides has been described. However, the present invention is not limited to the four sides.

Further, the mounting structure obtained according to the present embodiment can be resin-molded into a semiconductor package similarly to the first embodiment.

[0096]

According to the present invention, it is not necessary to perform fine processing and precise positioning on an intervening resin sheet in the related art, and it is possible to simplify the connection process in flip-chip mounting and improve the connection reliability between the semiconductor device and the circuit board. It can be improved.

Further, it is possible to sufficiently seal the four corners of the semiconductor device with resin, to improve the environmental resistance and mechanical strength of the electrode joint, and to ensure high reliability. Become. Thereby, the environmental resistance of the connection portion of the semiconductor device is improved, and the connection portion of the semiconductor device is mechanically reinforced, so that the reliability of the connection portion can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an example of a resin sheet of the present invention.

FIG. 2 is a diagram showing a configuration of a flip chip mounting structure according to the first embodiment.

FIG. 3 is a view for explaining one manufacturing process of the flip-chip mounting structure of FIG. 2;

FIG. 4 is a view illustrating a bonding step of the flip-chip mounting structure of FIG. 2;

FIG. 5 is a view showing the shape of a conventional sealing resin.

FIG. 6 is a view showing a shape of a sealing resin in the present invention.

FIG. 7 is a cross-sectional view showing a configuration in which the flip-chip mounting structure according to the first embodiment is packaged.

FIG. 8 is a cross-sectional view showing another example of the configuration in which the flip-chip mounting structure of the first embodiment is packaged.

FIG. 9 is a cross-sectional view illustrating still another example of a configuration in which the flip-chip mounting structure according to the first embodiment is packaged.

FIG. 10 is a cross-sectional view illustrating a configuration of a flip-chip mounting structure according to a second embodiment.

FIG. 11 is a diagram illustrating one manufacturing process of the flip-chip mounting structure according to the second embodiment.

FIG. 12 is a cross-sectional view illustrating a configuration of a flip-chip mounting structure according to a third embodiment.

FIG. 13 is a cross-sectional view illustrating a bonding step of the flip-chip mounting structure according to the third embodiment.

FIG. 14 is a view showing another example of the shape of the sealing resin in the present invention.

FIG. 15 is a diagram illustrating one manufacturing process of the flip-chip mounting structure according to the fourth embodiment.

FIG. 16 is a view illustrating a manufacturing step following FIG. 15;

FIG. 17 is a view illustrating a manufacturing step following FIG. 16;

FIG. 18 is a view illustrating a manufacturing step following FIG. 17;

FIG. 19 is a diagram illustrating a configuration of a flip-chip mounting structure according to a fifth embodiment.

FIG. 20 is a view showing another example of the resin sheet of the present invention.

FIG. 21 is a view showing still another example of the resin sheet of the present invention.

FIG. 22 is a front view and a cross-sectional view illustrating a configuration of the resin sheet of FIG. 21.

FIG. 23 is a view illustrating a manufacturing process of a conventional flip-chip mounting structure.

FIG. 24 is a diagram illustrating another example of a conventional flip chip mounting structure.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 semiconductor device 11 electrode of semiconductor device 12 projecting electrode on semiconductor device 13 projecting electrode on electrode of circuit board 20 circuit board 21 electrode of circuit board 23 resin layer 24 dam 30, 33, 35 resin sheet 32 sealing resin 34 printing resin

Claims (8)

[Claims] An interposition between a semiconductor device and a circuit board;
In a semiconductor device mounting resin sheet that flows and deforms due to heating during mounting to mechanically connect the semiconductor device and the circuit board, four diagonal corners have portions thicker than a central portion. A resin sheet for mounting a semiconductor device, comprising: 2. A device interposed between a semiconductor device and a circuit board,
In the resin sheet for mounting a semiconductor device, which flows and deforms due to heating during mounting to mechanically connect the semiconductor device and the circuit board, cuts for increasing the thickness of four diagonal corners by bending are provided. A resin sheet for mounting a semiconductor device, which is formed. 3. A flip-chip mounting method for mounting a semiconductor device on a circuit board by connecting a group of semiconductor electrodes of the semiconductor device to a group of substrate electrodes formed on a circuit board. A step of attaching a resin sheet having portions corresponding to four corners of the semiconductor device thicker than a central portion to a region inside the semiconductor electrode group or a region inside the substrate electrode group in the semiconductor device. Positioning the semiconductor device and the circuit board so as to face each other; bringing the semiconductor electrode group and the board electrode group into contact with each other, applying pressure and heating, and electrically connecting the electrodes. And simultaneously performing mechanical connection and sealing of the semiconductor device and the circuit board with the resin sheet by the resin sheet. . 4. A circuit board on which a semiconductor device is mounted, wherein portions corresponding to four corners of the semiconductor device in a region where the semiconductor device is mounted are formed so as to protrude toward the mounting surface side from other portions. A circuit board, comprising: 5. A flip chip mounting method for mounting a semiconductor device on a circuit board by connecting a substrate electrode group formed on the circuit board according to claim 4 to a semiconductor electrode group of a semiconductor device. A step of attaching a resin sheet to a region inside the semiconductor electrode group on the circuit board or a region inside the substrate electrode group in the semiconductor device; and causing the semiconductor device and the circuit board to face each other. The semiconductor electrode group and the substrate electrode group are brought into contact with each other, pressurized and heated, and their electrical connection and mechanical connection between the semiconductor device and the circuit board by the resin sheet are performed. A step of simultaneously performing connection and sealing. 6. A circuit board on which a semiconductor device is mounted, wherein a dam for suppressing the flow of a sealing resin is formed outside a region where the semiconductor device is mounted. 7. A flip-chip mounting method for mounting the semiconductor device on the circuit board by connecting the substrate electrode group formed on the circuit board according to claim 6 to a semiconductor electrode group of a semiconductor device. In the step of supplying a sealing resin to a region inside the semiconductor electrode group on the circuit board or a region inside the substrate electrode group in the semiconductor device, the semiconductor device and the circuit board Opposing and aligning; bringing the semiconductor electrode group and the substrate electrode group into contact with each other, applying pressure and heating, and electrically connecting the semiconductor electrode group and the circuit board with the sealing resin. A step of simultaneously performing mechanical connection and sealing with the chip, and a flip-chip mounting method. 8. A board electrode group formed on a circuit board,
In a flip chip mounting method for mounting the semiconductor device on the circuit board by connecting the semiconductor electrode group of the semiconductor device, a region inside the semiconductor electrode group on the circuit board or the substrate electrode in the semiconductor device A step of supplying a sealing resin to a region inside the group, a step of positioning the semiconductor device and the circuit board so as to face each other, and sealing around a mounting region of the semiconductor device in the circuit board. A step of disposing a resin shaping member; and, in a state in which the sealing resin shaping member is disposed, bringing the semiconductor electrode group and the substrate electrode group into contact with each other, pressurizing and heating, and electrically connecting them. And simultaneously performing mechanical connection and sealing of the semiconductor device and the circuit board with the sealing resin by the sealing resin. Method.